No hot water pressure when other taps are on.

rizy102 · 6 Apr 2008

hi,
i have 4 floors.
1st:kitchen
2nd:ravenheat combi boiler
3rd: toilet and sink
4th: bathroom w/ shower

the problem is that when having shower/bath, if someone else switches hot water on from anywhere downstairs the pressure of the bath/shower is very little or none. you have to wait until they turn the tap off from downstairs. then the pressure returns to full.
i need the pressure in the bathroom to have priority over everything else.
can anyone help please.
thank you

twgas · 6 Apr 2008

whats the pressure/flow rate at other taps like, including cold.

Saltire · 6 Apr 2008

Thats the most common complaint about combi boilers, they just dont have the power to supply more than 1 outlet at a time... No real easy fix other than advise everyone in the house when you are having a shower... .

andytheplumber · 6 Apr 2008

By the sounds of it you should not have had a combi fitted in the first place. A conventional system would have been better

rizy102 · 7 Apr 2008

flow at other taps is really good. just below full pressure.
is conventional system with a tank? cant really do that as there is no loft space at all.
also what about a seperate pump for bath/shower???
thanks

Saltire · 7 Apr 2008

you cant pump a combi boiler...

rizy102 · 8 Apr 2008

ok then. what about installing just a water boilier just for the bath/shower?
thanks

rizy102 · 17 Apr 2008

i think its called a multipoint water heater????
if so any recommendations? its only for the bath tap/shower.
thanks

kevplumb · 17 Apr 2008

http://www.chaffoteaux.co.uk/britonyflexiflue_001.php

you will still drop pressure when other taps are in use

JohnD · 17 Apr 2008

the bathroom is at the top of the house so is bound to have lowest pressure.

It is possible to have a hot water cylinder heated by a combi (although it is not common) which is the fastest way to fill a bath as the stored water is already heated ready for use, and you can pump it if you like a powerful shower. You can continue to use the combi hot water for kitchen etc. It doesn't sound like water supply to your house has good flow and pressure so you could use the familiar cold tank idea to supply the cylinder. Then you need have no loss of pressure from other users of taps.

It is possible to put the cylinder and a cold tank in an airing cupboard, since you say you have no loft space (it it a flat roof then?)

If a good shower is your top priority have a tank.

If not having a tank is your top priority put up with a poor shower.

plumbdev · 17 Apr 2008

i think an unvented system would be better here. cosidering you aint got the loft space for a tank, as long as you get the right flow rates and pressure at your property a MEGAFLOW should get rid of your problems

Lee

JohnD · 17 Apr 2008

but flow and pressure (at the top floor) does appear to be the problem

plumbdev · 17 Apr 2008

the problem with combi's are they run off 15mm pipe so when your demanding water at the top floor for your shower and someone else opens a tap somewhere else the pipe cant cope with the demand.. A megaflow or another unvented cyclinder will give you the 22mm pipe you need, but you might need to increase your incoming water main, also the exsisting 15mm pipework from the combi will have to be upgraded, i think you need to get someone round to do tests..

rizy102 · 18 Apr 2008

thank for the replies.
just another question. my cold water at top floor is actually quite good. if someone switches cold or hot water tap on from downstairs, the cold water flow is just below full pressure. will this not be sufficient for the multipoint?
thanks

rizy102 · 22 Apr 2008

anyone?

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No hot water pressure when other taps are on.

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